Update on my twin turbo project
 

As some of you know, I'm in the process of doing a twin turbo conversion on my blown 3.2 motor (using 993TT heat exchangers).

After much deliberating in terms of which turbo's I'm going to use for his conversion, I've decided to stick with the KKK solution, and go down the K16/16G hybrid path. This is mainly due to the fact that a lot of the 993TT and 996TT guys have had extremely good results with these babies. Also, I had some K16's lying around and it was only going to cost $1200 to have them rebuilt into hybrids with new, upgraded 1.0bar wastegates :D It was the cheaper option compared to buying new GT's and modifying the 993TT HE's :rolleyes:

I also considered the K16/24's, but wanted a little more airflow and efficiency than the K24 compressor wheels can provide. The Mitsubishi 16G wheels are a newer design and flow up around the 35lb/min each :eek: So in terms of total air flow, I should have around 70lb/min of total compressor.

As for exhaust design, I decided to hang a set of these Awe Tuning Muffler/Cat Bypass pipes off the K16/16G's... it will be seriously LOUD!

http://forums.pelicanparts.com/uploa...1238563131.jpg

I will shoot pics as I begin to bolt everything up on the car over the next couple weeks. I'm pretty excited to start on this project and can't wait for the end result.

Looking forward to the pics! Should be a beast!

James, that should sound nasty- how are you going to scavange the oil from the turbos?
I know I mentioned this earlier- I would use a tilton pump.

I hope your kkk 16 / 1.0 bar waste 993 type set up gates choices are good choices as I have one that is just being completed that was done in a similar fashion. Either that or misery loves company. I should get it on dyno then track this summer.

I'm using a better electric pump than the Tilton... it has a much higher scavenge capacity and is designed specifically for hot turbo oil. I think the Tilton units are more designed for transmission oil etc.

voitureltd - The word on the street is the upgraded 1.0bar wastegates are significantly better than the OEM units, which tend to be a bit lazy.

Those AWE pipes above are pretty expensive for what they are! $599 for the set! Ouch! :eek: I might just take the car down to my local exhaust fabricator and get him to custom make them on the car when everything is fitted up :cool:

The 1.0 bar actuators are good for fixed boost set ups as they hold the wastegate shut longer than stock 0.5bar units. Internal wastegate turbo's on Porsche started with the 993tt as you know, and from the 993tt up to the 997tt they are controlled by a Motronic ECU.
The motronic ECU senses air mass, and it adjusts the boost to stay within it's set air mass targets. Therefore giving less actual boost in cold weather than in hot weather, keeping the air mass the same. The problem with fitting these 1.0bar actuators on a Motronic controlled car is this, if the ECU senses danger it would usually open the wastegates and limit the boost to 0.5bar, limp mode so to speak, it cannot do this with these 1.0bar units so it can only then cut the spark.

The top European tuners keep full Motronic control, the wastegates may start to open sooner but they are tuned to suit this. For instance the K24/26RS units designed and used by RS tuning are used up to about 580 "engine dyno" BHP at about 1.2bar. I do not doubt that these turbos would give significantly more power running fixed boost, with stronger actuators it would keep the wastegates shut tight longer not allowing any boost to bleed off, with the 0.5bar actuators they will start to open at 0.5bar but boost will still build, when the air mass target is reached the N75 valve is opened by the ECU and the actuator opens further keeping the boost in check. With a 1.0bar actuator they will start to open at 1.0bar only, if your boost target is 1.0bar then you may get boost creep (this is a guess), i'm not sure how far a 1.0bar actuator will open if it is shown 1.0 bar from the N75 valve, i guess it depends on how much preload is set.

I know a stock 0.5bar actuator is properly set up when fitted to the turbo and you add preload until it opens exactly 4mm with 0.5bar of pressure. This is what the ECU is set up to expect. Pressure in the turbo pushing against the wastegate will start to open the wastegate at 0.5bar, but as i said earlier boost still builds, it's only when the N75 vlave opens and the actuators move further that boost is controlled.

Are you going to run a fixed boost set up on your car? If so what is your boost target?

Interesting, Jonathan.

I have an EBC which I will use to regulate boost with, over 1.0bar. I plan to set the EBC to regulate up to 1.25 bar.

The 3.2 Carrera Motronics isn't as "smart" as the 993tt/996tt ECU's. The programming in my Protomotive MAP ECU is calibrated for up to 1.4bar.

I suppose as long as you don't want to run less than 1.0bar you'll be fine.
So your ECU is pressure sensing? You don't have to do anything other than set your EBC to whatever boost level and the ECU compensates and adds fuel accordingly, I know bugger all about that stuff, it's interesting though, can you tell us more

All I know is that the Protomotive Pressure Sensing ECU compensates for any boost level up to 1.4bar, and works in conjunction with their custom FPR, injectors and software maps.

Even changing to a larger throttle body, Proto says the ECU auto compensates and adjusts fuel and changes the ignition according to load.

It's just the way Proto designed the system. Seems to work very well.

I know the later 993tt/996tt ECU's require re-flashing for any changes to VE... I guess they aren't as forgiving as the earlier 3.2 Motronics due to all the added intelligence and complexity? I have no idea about that generation Motronic tho.

I'm sure aftermarket ECU's like Motec or Autronic are much more programmable, but the Proto solution works very well for a plug and play system.

Sounds like an absolutely great system James! Dial in your boost and the ECU does the rest :cool:

I don't think Motec allows for sensing knock, in fact i'm not sure it really has much in the way of saving the engine if anything goes wrong, not sure about other ECU's?
Lets say with your ECU an injector goes bad or something, and it starts running lean or the EGT's go way up, does the ECU cut ignition or boost to save the motor? Do you know if Motec ECU's do this too?

The main bonus of the Motronic ECU, in the turbos from 993tt up, is the amount of safety they offer, they can cut boost to 0.5bar and/or cut ignition to save the motor if necessary, they sense everything from knock to pre/post CAT AFR, CHT to IAT. The major downside being there are only a handful of people in the world who can map it "properly" and keep full Motronic control. There are probably hundreds of people who can offer fixed boost type programming, the problem being the car behaves different in varying temps.

My car runs great in anything from say 7 degrees C up to hot temps, however in really cold weather the ECU pulls boost, basically the map i have isn't programed properly to compensate for the extra air mass cold air gives, and this is from a recognised expert here in the UK. It's a little frustrating to be honest, it's been back about 6 times to get sorted but still isn't absolutely right. I should have bought the RS Tuning kit, a properly developed package, it's damned expensive though :(

Does your program compensate for ambient temps, would it allow you to run 1.4bar in 0 degrees C for instance? As obviously 1.4 bar at 0 degrees C is a major difference to 1.4bar at 25 degrees C. I'm still getting my head round all this stuff so forgive me for being a bit green :)

I haven't kept up lately, what kind of power are you expecting?

The first generation Carrera Motronic is a VERY basic system... no knock sensing whatsoever! It only measures IAT, MAP sensor, CHT, TPS and the other factory Carrera sensors (speed sensor etc).

It compensates very well for ambient temps as fair as I can tell. I really want to get a LM1 and log more data, such as AFR vs RPM vs Load/Boost etc... only then will I know what it's really doing and how well it's calibrated. One annoying this is when it's cold, I think the mixture is too rich and it tends to have a flat spot under hard accel, but this quickly resolves itself as the engine/oil temps rise.

jbrinkley, I'm really not sure what to expect to be honest. At 1.25bar, I'll probably be around 550-600 flywheel HP at a guess. This is based on the Proto Stage 3 build specs of course (3.3, 7.0:1, GT2-EVO CAMs). One thing is for sure, I have the turbo's to take me where I'd like to be.... I hope :confused:

Even if I don't make it there, ah well... it's going to be fun, and unique nonetheless :)

do you need an I/c or an intake I have one reall y nice sitting waiting to be converted to single turbo tanks. it was made by mark hargett

I can't even imagine how fun that will be. I once rode in a 996t with the proto 750, or 700 kit, I imagine it'd be like that kinda, definitely a hold on and laugh all the way down the street kinda ride.
cool

James, does Protos MAP sensing Motronic still use the AFM then?

No, the AFM is completely removed and the IC is plumbed directly into the throttle body... zero restrictions. I do plan to upgrade the TB at a later stage, from the factory 63mm to a 70mm unit. Should make a nice difference.

Basically the same as the Yellowbird then?

Interesting project, keep the updates coming. I'm converting my 930 to EFI. I plan on using the 3.2L Motronic system, converted to MAF and running a wasted spark. In addition, the Motronic will be able read a boost sensor to alter ignition as required. It will retard ignition significantly in the case of overboost. I will also incorporate a Zeitronix Wideband system with EGT. The Zeitronix will allow the user to set complex alarms (ex. Boost higher than xPSI and AFR leaner than 12:1 and/or EGT higher than xF). The Alarms will be sent to the DME to shut thing down (similar to a rev limit).
Anyone can recommend a good knock display system?

I presume so? Alois based the Yellowbird's Motronics on the 962 Motronic system, which is also a pressure sensing setup :cool:

I'm also considering using a pair of these K&N intake systems for my intakes. They even have a vacuum port for the Motronics ICV/ISV with barbed fittings that come in sizes: ¼” OD, 3/8” OD, ½” OD or 5/8” OD. They are rated at 350HP each, in a turbocharge application, which is ideal for the K16/16G's :D

http://forums.pelicanparts.com/uploa...1238724955.jpg

james, pm sent...